Earth compaction pads

ABSTRACT

Compaction wheels are convertible from sheepsfoot configuration to other configurations such as rectangular pads and have rigidly attached peripheral shanks for mounting removable, wear-cap holders equipped with replaceable, abrasion-resistant metal wearcaps. In certain embodiments the wear-cap holders are secured rigidly to the wheel periphery.

United States Patent [191 Caron et a1.

[11] 3,822,957 [451 July 9, 1974 1 1 EARTH COMPACTION PADS [75] Inventors: Fred Joseph Caron, Citrus Heights;

James Oliver Caron, Sacramento, both of Calif.

[73] Assignee: Caron Compactor Co., West Sacramento, Calif.

[22] Filed: Oct. 24, 1972 [21] App]. No.: 300,136

Related US. Application Data [63] Continuation-in-part of Ser. No. 179,097, Sept. 9,

1971, abandoned,

[52] US. Cl. 404/121, 37/141 T, 301/44 T, 4 172/554 [58] Field of Search E01c/19/26; 404/121, 122; 37/141 R, 141 T, 142 R; 172/554, 556, 719;

5/1941 Austin 404/121 2,312,471 3/1943 Low 404/121 2,334,778 11/1943- LeTourneau 404/121 2,369,285 2/1945 Daniels 37/142 R 2,893,298 7/1959 Averette 404/121 3,274,908 9/1966 Grant 404/121 3,313,222 4/1967 Barnum 404/121 3,431,664 3/1969 Creager 37/142 R 3,585,741 6/1971 Heusler 37/141 T 3,650,185 3/1972 Takata..... 404/121 Primary ExaminerNile C. Byers, Jr. Attorney, Agent, or Firm-Flehr, Hohbach, Test, Albritton & Herbert 1 1 ABSTRACT Compaction wheels are convertible from sheepsfoot configuration to other configurations such as rectangular pads and have rigidly attached peripheral shanks for mounting removable, wear-cap holders equipped with replaceable, abrasion-resistant metal wear-caps. In certain embodiments the wear-cap holders are secured rigidly to the wheel periphery.

20 Claims, 27 Drawing Figures PATENTEUJUL 91914 3.82295? sum 1 or 7 INVENTORS I Fred Joseph Caron F I g. BY James Oliver Caron PATENTEDJUL 3,822,957

SHEEI 2 0F 7 INVENTORS. Fred Joseph Caron. BY James Oliver Caron we, W,m W @W INVENTORS Fred Joseph Ca By James Oliver Car ;w,., W,m

%??orneys PATENTEDJUL 1 4 3,822,957

saw 7 or 7 II IIIIII EARTH COMPACTION PADS CROSS-REFERENCE TO RELATED APPLICATION This is a continuation-in-part application of copending application Ser. No. 179,097, filed Sept. 9, 1971 now abandoned.

BACKGROUND OF THE INVENTION This invention concerns improvement to earth tampers and particularly earth compaction wheels which are readily convertible from one configuration of compaction pads to another, the compaction pads including replaceable wear-caps.

Compaction wheels or rollers in the past have been designed for specific applications. To this end, the compaction pads of the wheels had compaction surfaces which were either circular or generally rectangular in outline depending upon the intended service for the wheel. An operator undertaking compaction projects requiring differing configurations of compaction pads necessarily included among his equipment compaction wheels of all the common specified configurations so as to be able to perform according to the project specifications. Compaction wheels which could be readily converted from one to another of the specified configurations would be advantageous in that an operator could reduce his inventory of compaction equipment.

Replaceable portions for compaction pads or lugs are known in the art as shown in the US. Pat. to Edminster, No. 3,340,073, issued Sept. 12, 1967. However, the dovetail connection of the replaceable portion to the support as shown there has not been satisfactorily applicable to a wide variety of the commonly used compaction pad configurations. Desirably, a replaceable wear-cap should be united to the underlying support both mechanically and through use of welding techniques which operators of compaction equipment commonly employ in maintenance operations.

SUMMARY OF THE INVENTION AND OBJECTS In summary the invention includes an annular wheelrim member having a plurality of spaced shank members extending radially outwardly from its outer surface, the shank members being each equipped with radially opening sockets. Wear-cap holders are removably mounted in said shank sockets, the holders including enlarged head portions arranged outwardly of the Another object of the invention is toprovide an improved earth compaction apparatus having compaction pads including abrasion-resistant metal wear-caps which may be installed and removed from an associated support through use of metal welding techniques. v

Another object of the invention is to provide an improved wear-cap and holder which are mechanically interconnected by an improved joint.

Another object of the invention is to provide an improved compaction pad having a replaceable wear-cap portion separate from the cap holding portions to en able the wear-cap to be made of a harder material than the remainder of the compaction pad without greatly increasing the cost of such compaction pad.

Another object of the invention is to provide, in a compaction pad of the type described, for the combination of the shank and holder portions in a unified structure.

Another object of the invention is to provide for the mounting of the wear-cap holder portion directly to the associated compaction wheel.

Another object of the invention is to provide for fixing of a one-piece wear-cap directly to the wear-cap holder wherein removal of the wear-cap may be achieved without the destruction of the holder.

Other objects and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments considered in connection with the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 5 is a view like FIG. 3A of the embodiment shown in FIG. 4;

FIG. 6 is a view like FIG. 1 but showing a third embodiment of the present invention;

FIG. 7 is an enlarged sectional view taken along the lines 7-7 of FIG. 6;

FIG. 8A is an exploded, perspective view of the wearcap and holder assembly of the embodiment shown in FIG. 7;

FIG. 8B is a perspective view showing the wear-cap I and holder of FIG. 8A in the assembled condition;

FIG. 9 is a view like FIG. 7 but showing a fourth embodiment of the present invention;

FIGS. 10A and 10B are views like FIGS. 8A and 88, respectively, but showing the embodiment of FIG. 9;

FIG. 11 is a view like FIG. 7 but showing a fifth embodiment of the present invention;

FIG. 12 is a sectional view taken in the direction of the arrows 12-12 of FIG. 11;

FIGS. 13A and 13B are views like FIGS. 8A and 88, respectively, but showing the embodiment of FIG. 11;

FIGS. 14A and 14B are exploded, perspective views but showing a sixth embodiment of the present invention;

FIG. 14C is a perspectiveview of the embodiment of FIGS. 14A and 14B showing the part in the assembled condition;

FIGS. 15, 16 and 17 are sectional views taken in the direction of the respectively numbered arrows of FIG. 14C;

FIG. 18A is an exploded, perspective view of a seventh embodiment of the present invention;

FIG. 18B is a perspective view showing the embodimentof FIG. 18A in the assembled condition;

FIG. 19 is a sectional view taken in the direction of the arrows 1919 of FIG. 18B; snd

FIG. 20 is a sectional view taken in the direction of the arrows 20-20 of FIG. 19.

DESCRIPTION OF THE PREFERRED EMBODIMENTS There is shown in FIG. I of the drawings a compaction wheel made in accordance with and embodying the principles of the present invention and having mounted upon the outer periphery thereof a plurality of compaction pads 11 each including a shank member 12, a holder 13 and a separate, replaceable wear-cap 14.

The compaction wheel 10 may be constructed in accordance with the disclosure contained in co-pending application Ser. No. 122,746, filed March 10, 1971, entitled Compaction Wheels for Earth Tampers which issued as US. Pat. No. 3,724,342 on Apr. 3, 1973. Accordingly, as described in that application, the wheel 10 may be mounted upon either a self-propelled vehicle or towed by a tractor which two forms of construction require specific adaption of the hub mounting structure, all as well understood in the art. As shown in FIG. I, the wheel 10 is one adapted for mounting upon an axle 16 operatively connected to a towed frame (not shown). The wheel 10 includes an outer drum member 17 resiliently mounted at six points to the wheel spider assembly 18 which in turn is bolted to the axle mount 19. A plurality of axially spaced apart outer rings 21 or rim members is each supported from the drum 17 by the tubular spacer elements 22, one being mounted radially inwardly of every second compaction pad 11, as shown in FIG. I.

As previously mentioned, each compaction pad 11 includes a shank member 12 which supports the dismountable wear-cap holder 13 upon which is fixedly secured the wear-cap 14 which is formed from hard, abrasion-resistant material. The pad shank member 12 is fixedly'secured, such as by welding, to the outer ring or wheel rim member 21 and to this end, the shank member is formed with a broad case so as to supply a substantial amount of surface for welding contact, as well as to transmit over a long service life the earth compaction forces efficiently onto the ring 21. Centrally the pad shank member is provided with a tapered socket or hole 23 (FIG. 2) having its broadest diameter at the outer or distal end 24 of the shank member. A

Morse standard taper, approximately five-eighths inch per foot, has been found to be an acceptable taper for the hole or socket 23 providing selfholding of the associated, complimentary pin portion 26 of the cap holder 13 because of the small angle (2 or 3) of taper.

The wear-cap holder 13 includes a tapered pin portion 26 frictionally received within the socket 23. A head portion 27 is integral with the pin portion 26 merging at a neck or recessed portion 28. The head is block-like in configuration, is elongated in the rolling direction of the wheel and is rectangular in plan view (FIG. 3A). Formed in the longer side walls of the head portion 27 are elongated recesses 29 which, in lateral cross-section (FIG. 2), are generally semi-circular and extend the full length of the head 27. The wear-cap holder 13 and shank 12 are configurated so that force transferbetween these parts occurs between the pinlike member 26 and the tapered side walls of the socket 23. To this end the neck 28 and head 27 portions of the wear-cap holder both are normally disposed spaced apart from the distal end 24 of the pad shank 12, as clearly shown in FIG. 2.

So as to resist forces tending to rotate the wear-cap holder with respect to the shank 12, and particularly the pin element 26 with respect to the socket or tapered opening 23, a mechanical provision is included in the form of a key 46 and keyway 47 are formed respectively along the hole 23 of the shank and the pin 26 to extend longitudinally thereof (FIGS. 4 and 5). Further insuring against loss of the holder 13 from the shank 12 a carriage bolt 31 is arranged between the shank and pin and is received within a narrow elongated opening or slot 32 which extends through the pin 26, as shown in FIG. 3A. A hole 33 extending axially of the wheel 10 is provided in the shank and is of a size for easy insertion of the carriage bolt 31 and for tightening of the nut 34 by a socket wrench or the like (not shown).

As previously mentioned, the wear-cap 14 is fixedly secured to the holder 13 and to this end the wear-cap is composed of two identical, hollow, heavy shell-like wear-cap halves 36. Each wear-cap half 36 includes longitudinally extending side walls 37, and end wall 38 and an earth-engaging compaction wear-face 39 (FIGS. 3A and 3B). The side walls 37 on the inside are provided with inwardly projecting, longitudinally extending, semi-circular rail-like members 41 shaped complimentary in cross-section to the side recesses 29 of the holder, as may be seen from FIG. 2. The rail-like members desirably extend the full length of the inside of the walls 37. The inside of the hollow wear-cap halves 36 is configurated to facilitate sliding thereof onto the head portion 27 of the wear-cap holder to be mechanically interlocked thereto by means of the members 41 seating in the recesses 29 to establish a tongue-and-groove joint.

' To insure that the wear-cap halves remain securely on the holder 13, the halves are welded together. To

this end the inner or confronting portions of the wear- I faces 39 are provided with a bevel 42 to establish a veeshaped weld joint for the receipt of weld metal 43 (FIG.

38) across the face 39. The weld metal may be extended in a seam 44 down the side walls 36 so that the wear-cap 14 is held rigidly and snugly with respect to the head portion 27 of the holder 13 by both the mechanical connection between the elements 29 and 41 and by the welded joints 43 and 44. In this condition the inside surfaces of the hollow wear-cap engage the head portion 27 over a broad area and little, if any, relative movement is present during earth compaction service. This provides a transfer of forces through the wear-cap to the holder principally in compression with a minimum of bending whereby the wear-cap wall thickness may be selected on the main criteria of resisting earth abrasion to provide a long service life, rather than on the basis of resisting bending stress.

The wear-cap halves are formed by casting or appropriate forging methods from ferrous alloy materials especially adapted to resist abrasion encountered in earth weld joint 42 across the broad wear-face 39 has been found to be a desirable featureof the present invention, as has providing a butt joint between the confronting side wall portions 36 of the wear-cap halves. This arrangement of the weld joint provides for the reduction of weld stresses created as the hard material of the wear-caps is welded.

Operation After a substantial period of compaction service, when the wear-caps 14 are to be replaced, the weld metal joints are broken through the use of compressedair-carbon are electric welding techniques to remove the weld metal for separating the wear-cap halves so that they may be dismounted from the holder 13. A new pair of wear-cap halves may then be mounted on the holder and weld metal deposited in the joint between the two elements.

An advantage of a two-piece shell-like or hollow wear-cap with the beveled welding joint across the wear-face 39 is that the weld joint seals the cap against dirt penetration, provides a strong joint while protecting the underlying holder, a relatively more expensive element. It will be recognized that the weld joint 42 does not involve'welding the wear-cap directly onto the holder but welding only the two cap halves 39 together. Thus the wear-cap may be dismounted without damage to the holder.

The subject combination of a wear-cap and holder dismountable from a shank permanently secured to a compaction wheel permits ready .conversion of the wheel from one configuration to another, as may be dictated by work requirements. For example, a compaction machine operator may be required to furnish a sheepsfoot wheel having specified pad area to a project. With the present invention, the operator may readily convert from the flat pad to the sheepsfoot configuration by removing the carriage bolt 31 from the shank,- removing the holder and wear-cap unit and mounting the specified unit in the shank. Thus with the present invention it is unnecessary to maintain separate compaction wheels or vehicles for each of the many earth compaction requirements.

Second Preferred Embodiment A second preferred embodiment 51 of the present invention is shown in FIGS. 4 and 5 wherein like reference numerals are used to designate the like parts described previously: the shank member 12, the tapered socket or hole 23, key 46, keyway 47, carriage bolt 31, the hole 32, nut 34 and the axial hole 33. The embodiment 51 includes a wear-cap holder 52 and a twopiece, hollow or thick shell-like wear-cap 53.

The holder 52 includes a tapered pin 54 similar in construction and function to the pin 26 described above, the pin 54 being integral with a rectangular, block-like head portion 56, as shown in FIG. 5. The holder 52 is configurated so that the head portion 56 projects or extends above the distal end 24 of the shank so as to provide a recessed region or portion 57 between the lower surface of the head 56 and the shank distal end 24 (FIG. 4).

The wear-cap 53 is composed of two identical halves, each having a beveled portion 42 providing, when assembled together, a vee-weld joint for uniting the two halves. The wear-cap 53 has a flat rectangular wearface 61 integral with the end wall 62 and depending side walls 58. Each side wall is equipped along its lower border with an inwardly projecting rail member 59 which is received in the recessed region 57 of the holder serving to retain the wear-cap with respect to the holder 52.

Third Preferred Embodiment A third preferred embodiment 71 of the present invention is shown in FIGS. 6, 7, 8A and 8B and includes the following parts previously described: the shank member 12 having the tapered opening 23, key 46, keyway 47, and the axially disposed hole 33, the carriage bolt receiving opening 32, the carriage bolt 31,

' nut 34, and the outer wheel ring 21.

The embodiment 71 pertains to a compaction pad of circular or sheepsfoot configuration as contrasted to the generally rectangular configuration of the pads of the two embodiments 11 and 51 described above. The compaction pad 71 includes, in addition to the parts previously mentioned, a wear-cap holder 72, a twopiece, hollow, thick shell-like wear-cap 73 and a welding backup plate 74.

The wear-cap holder 72 includes a tapered pin portion 76 similar in construction and function to the pin 26 previously described. The pin is equipped with the transversely extending, rectangular cross-section hole 32 to receive the carriage bolt 31 for the purposes described above. The holder 72 is configurated so as to provide extending above the distal end 24 of the shank a circumferentially extending, recessed portion 77 which, in vertical cross-section, is generally semicircular. Above the recessed portion 77 the holder 72 includes a head portion 78 which is circular in plan, as clearly shown in FIG. 8A.

The wear-cap 73 comprises two identical wear-cap halves 79 which, when united by the weld seam 81 (FIG. 8B), become a unitary, hollow wear-cap. The cap 72 is provided with the flat, annular compaction face which surrounds a frustoconically shaped cup 85, the bottom of which is provided with a hole 83 for plug welding the cap to the circular backup plate 74. The curved side walls 86 of the wear-cap are rounded, as at 87 in FIG. 7, along the lower end to facilitate clean withdrawal of the cap from the earth. An inwardly projecting, circular rail 82 is arranged on the free end of the depending side walls 86 of the wear-cap halves 79, the rail being configurated to cooperatively engage in a snug relationship the recessed or necked down portions 77 of the holder 72, as shown in FIG. 7. In this relationship the head portion 78 and the weld backup or holder protection plate 74 are received within the hollow body of the wear-cap.

So that the two wear-cap halves 79 may be securely welded together without inducing undesired welding stresses in the hard, wear-resistant material, a center hole 82 is arranged in the top surface of the wear-cap. Flanking the hole 83, the wear-cap halves are each beveled-as indicated at 84 in FIG. 7 to provide a vee-joint to receive weld metal 81. The weld backup plate 74 is provided at the top of the head portions 78 so that the weld 81 can be carried across the entire wear-cap face without the danger of welding the cap directly to the holder. The weld seam 81 may be carried down to the side walls of the wear-cap as indicated at 88. When worn to a condition beyond compaction specifications, the wear-cap 73 may be dismounted from the holder 72 by employing, for example, the compressed-air-carbon are metal removal operation along the weld seam 81 thereby cutting the wear-cap again into halves without damage to the holder 72. A new wear-cap 73 may be installed upon the holder 72 and welded into place for extending the useful life of the compaction pad 71.

Fourth Preferred Embodiment A fourth preferred embodiment 91 is shown in FIGS. 9, 10A and 10B and includes the following parts previously described: the outer wheel ring 21, the shank member 12 having the tapered opening or socket 23, key 46, keyway 47, and the axially arranged hole 33,

the carriage bolt 31 and nut 34, and the wear-cap holder 72 having the head portion 78 arranged outwardly of a recessed or neck-like portion 77. The compaction pad 91 includes, in addition to the parts previously mentioned, a two-piece, hollow wear-cap 92 and a welding backup plate 93.

So as to permit limited relative movement between the wear-cap 92 and the wear-cap holder 72, a ball and socket bearing is provided. More specifically, the head portion 94 of the holder is provided with a convex spherical surface 96 (FIG. 10A) and the backup plate 93 is provided with a concave spherical surface 97 on one side and a flat surface 98 opposite therefrom (FIG. 9) so that when the backup plate 93 is plug welded to the wear-cap 92, limited relative movement between the wear-cap and backup plate unit 93 is permitted with respect to the head portion 94 of the holder. The range of relative motion between the wear-cap and holder may be largely attributable to dimensional allowances in manufacturing and is limited by the engagement of the rail portions 82 in the complimentary recesses 77. The provision of the mating spherical surfaces insures that such relative movement as does occur will distribute stresses more evenly between the wear-cap and head portion of the wear-cap holder, reducing localized stresses.

Fifth Preferred Embodiment A fifth preferred embodiment 101 is shown in FIGS. l1, 12, 13A and 13B and includes the following parts previously described: the outer wheel ring 21, the shank member 12 having the tapered opening or socket 23, key 46, keyway 47, the axially arranged hole 33, and the carriage bolt 31 and nut 34. The compaction pad 101 includes, in addition to the parts previously mentioned, a wear-cap holder 102 having a head portion 103 arranged outwardly of the pin portion 26 and a one-piece, hollow, heavy shell-like wear-cap 104.

The head portion 103 of the wear-cap holder 102 is provided with a substantially flat top surface 106 which extends outwardly to overhand a neck portion 107 defined at the juncture between the pin and head or platform portion 103. Referring to FIG. 13A, it will be seen that a portion of the head or platform 103 is thickened and extends outwardly from the pin portion to provide a chain 108, the outer surface of which is formed on the same radius as the side walls of the wear-cap 104. The key 46 in the shank 12 and keyway 47 in the holder 102 are arranged to position the chin 108 and weld joint 118 to extend parallel to the wheel rolling direction serving to reduce dynamic forces on the weld joint.

The wear-cap 104 is of one-piece, hollow, heavy shell-like construction and its compaction surfaces include a flat annular face 109 which surrounds a centrally disposed, depressed circular area 111. A combination side and end wall 112 of curved arrangement extends at a right angle away from the compaction surfaces 109, 111 and terminates in an inwardly projecting rail or flange 113, which, in plan view (FIG. 13A), has a general configuration of a horseshoe defining an opening in the bottom of the wear-cap. An opening 114 is provided in one sector of the wear-cap wall 112 for receipt of the head or platform portion 103 of the wearcap holder. The opening 114 is formed in the wall and flange members 112, 113 so as to provide access to the wear-cap inner face 116 so that when the holder and wear-cap are united, as indicated by an arrow 117 in FIG. 13A, the faces 106, 116 will be in engagement, as shown in FIGS. 11 and 12. When the holder and wearcap are in the assembled condition, the head portion 103 is snugly received within and enclosed by the hollow portion of the wear-cap defined by the walls and flange 113, and the flange 113 projects inwardly towards the neck portion 107 of the holder providing a mechanical joint between the wear-cap and holder.

To maintain the wear-cap and holder fixed in the assembled condition a weld metal joint 118 is formed between the chin portion 108 of the holder and the adjacent side face of the wear-cap, as shown clearly in FIGS. 11 and 13B. Facilitating formation of the joint, the confronting portions of the wear-cap and holder are equipped with bevel-like indentations 119 providing a veeelike joint for the receipt of the weld metal. When it is desired to replace a worn wear-cap 104, the weld metal joint 118 is broken through the use of techniques well known in the art. Being that the chin portion 108 presents a thick mass of metal at the joint area, removal of some of this material during the joint breaking operation will not affect the effectiveness of the holder for the reason that any metal removed can be simply replaced by the deposit of weld metal when mounting the new wear-cap. The holder 102 and wear-cap 104 are oriented in the shank 12 by the key 46 and keyway 47 so that the weld joint 118 faces towards the side of the wheel and not in the rolling direction.

Sixth Preferred Embodiment A sixth preferred embodiment 121 is shown in FIGS. 14A, 14B, 14C, 15, 16 and 17 andincludes the outer wheel ring 21 previously described above. The compaction pad 121-also includes a two-piece, hollow, heavy shell-like wear-cap 122 and a wear-cap holder The wear-cap holder 123 is adapted to be rigidly secured directly to the wheel ring 21 and to this end, a central channel 124 extends along the underside of the body of the wear-cap holder from end to end, as clearly shown in FIG. 14A. The channel 124 serves to receive the wheel ring 21, as shown in FIGS. 15 and 16, and deposited weld metal 126 serves to retain the holder on the wheel ring 21. The holder 123 includes a block-like head or platform portion 127 which is integral with a base portion 128 and a neck or recessed or undercut portion 129. It will be appreciated that the holder is elongated in the rolling direction of the wheel. The

neck portion 129 is defined by recesses which extend across the shorter ends of the holder and down the longer sides about one-quarter of the length of the head portion 127. A top surface 131 of the holder is substantially flat and the sides are arranged substantially perpendicular thereto and are perpendicular to the base 128 which extends laterally outwardly on all sides of the head or platform portion 127, as shown best in FIG. 148.

As previously mentioned, the wear-cap 122 is fixedly secured to the holder 123 and to this end, the wear-cap is composed of two identical, hollow or thick-shelled wear-cap halves 132. Each wear-cap half includes longitudinally extending side walls 133, an end wall 134 and a ground compaction wear-face 136. As shown in FIGS. 14B and 14C, each wear-cap half is open along the bottom and along one end. The end wall 134 along the lower portion thereof is provided with an inwardly projecting, semi-circular rail-like member 137 shaped complimentary in cross-section to the recesses or neck portions 129 of the holder, as may be seen from FIG. 17. The rail-like members desirably extend the full length of the end wall 134 and along the side walls 133 to about one-half the length of the wall 133 and are of a length complimentary to the recessed portion in the holder. The rail-like members or protrusions 137 on the wear-cap halves are configurated to facilitate sliding of the wear-cap onto the head portion of the wearcap holder to be received within the recess or neck portion 129 and to form a mechanical interlock between the wear-cap and holder in the relationship of a tongueand-groove joint.

Insuring that the wear-cap halves 133 remain securely on the holder 123 the halves are welded together. To this end, the inner or confronting portion of the wear-cap faces 136 is provided with a bevel-like indentation 139 to establish, when the'parts are joined together, a vee-shaped weld joint for the receipt of weld metal 141 across the wear-face 136. When the wear-cap halves are assembled together on the holder and welded together, there is afforded a rigid and snug fit with respect to the head portion of the holder by both the mechanical connection of the protrusions or rails 137 and the neck portion of the holder 129, and

' by the weld joint afforded at 141. In this condition the inside surface of the hollow wear-cap encloses and engages the head portion over a broad area and little if any relative movement is present during earth compaction service. This provides a transfer of forces to the wear-cap to the holder principally in compression with a minimum of bending.

Seventh Preferred Embodiment A seventh preferred embodiment 151 is shown in FIGS. 18A, 18B, 19 and and includes an outer wheel rim member 152, a two-piece, hollow, thick shell-like wear-cap 153 and a wear-cap holder 154.

The wheel rim member 152 may be an outer wheel ring 21 as described above or may be a member forming the surface of an outer wheel drum of a compaction roller, as is well known in the earth compaction field. In any case, the wear-cap holder 154 is welded directly to the outer wheel member 152, the holder having a base portion 156 of generally rectangular outline and may be welded as indicated at 157 to the wheel member 152 so that the longer dimension of the base extends in the direction of the wheel axle. The wear-cap holder 154 is provided with a head portion v158 which has inclined end faces 159, inclined side faces 161 and generally flat top faces 162. A channel 163 is formed in the head portion 158, the channel extending the full height of the head portion to the base 156. The function of the channel 163 will be described below. The channel 163 divides the head portion 158 into two, pyramid-like bodies which are each united to the base at recessed or undercut neck portions 164. Thus the head portion of the holder at its outer periphery overhangs the base portion, as clearly shown in FIG. 20.

As previously mentioned, the wear-cap 153 is fixedly secured to the holder 154 and to this end, the wear-cap is composed of two identical, hollow, thick shell-like wear-cap halves 166 which, in the assembled condition as shown in FIG. 188, have the configuration of a solid inverted vee. Each wear-cap half 166 includes two inclined, longitudinally extending side walls 167 and an end wall 168 arranged perpendicular to the side walls and defining an opening along the bottom and at one end. The side walls 167 are so dimensioned that when the wear-cap is assembled on the holder that the side walls will shroud and, together with the end wall 168, will entirely enclose the wear-cap holder. The side walls 167 converge at a narrow, somewhat rounded, ridge portion 169 which serves as a destructive edge for the compaction pad 151 for grinding and crushing. The side walls 167 and end wall 168 on the inside are provided with an inwardly projecting, longitudinally extending, semi-circular rail-like members or protrusions 171 shaped complimentary in cross-section to the recesses 164 of the holder, as may be seen from FIGS. 19 and 20. The rail-like members 171 desirably extend the full length of the inside of the walls 167 and along the inside ofthe end wall 168, as illustrated in FIG. 19. The

inside of the hollow wear-cap halves 166 is configurated to facilitate sliding thereof onto the head portion of the wear-cap holder, the protrusions or rails serving with the recessed or neck portion 164 to form a mechanical interlock in the nature of a tongue-and-groove oint.

Insuring that the wear-cap halves remain securely on the holder the halves are welded together. To this end, the inner or confronting portions of the wear-cap faces 167 are provided with'bevel-like indentations 172 to establish a generally veeor U-shaped weld joint for the receipt of weld metal 173 (FIG. 188) along the faces 167. The weld metal may be extended in a seam down the faces 167 for the full length of the groove. Thus the wear-cap is held rigidly and snugly with respect to the head portion of the holder by the mechanical connection between the elements held together through the welded joints 172. In this condition, inside surfaces of the hollow wear-cap engage the head portion over a broad area and little if any relative movement is present during earth compaction service After a substantial period of compaction service, when the wear-caps 153 are to be replaced the weld joint 173 is broken through the use of techniques well known in the art. The channel 163 during the wear-cap removal operation serves to permit the burning through of the molten metal and to provide for the escape of molten metal as the weld joint 173 is cut. A new pair of wear-cap halves may be mounted upon the holder and the weld metal deposited in the joint between the two elements.

It will be apparent from the above that there has been described an improved compaction pad wherein the portion subjected to the harshest wear, the wear-cap, may be dismounted and replaced through use of conventional welding techniques. The provision of the wear-cap of relatively small, but more expensive, metal mass in relation to the mass of the overall compaction pad provides economies in use of the pads of this invention. Moreover, a variety of different shaped wear-caps may be mounted upon the associated holders 12 while each holder is retained securely with respect to the wheel through the associated shank member (in certain embodiments) by an inexpensive and easily replaced carriage bolt 31 which not only prevents rotation of the wear-cap holder combination with respect to the shank, but insures that the holder will not inadvertently disengage and become dismounted from the shank member and compaction wheel. In other embodiments the holders are rigidly secured to the wheel periphery.

It will be apparent to those having ordinary skill in the art that many changes may be made in the details of the preferred embodiments of the invention described above without departing from the spirit of the invention. Therefore, the scope of the present invention should only be determined by the following claims.

We claim:

l. A renewable pad for a compaction wheel comprising a shank having a base adapted to be fixedly secured to a compaction wheel, a longitudinally extending, centrally arranged hole in said shank, a wear-cap holder removably mounted in said shank and having a proximal end inserted into said hole and a distal end projecting therefrom, a hollow, replaceable wear-cap mounted on the distal end of said holder, said holder being configurated to include a recessed region about said distal end, said wear-cap including an internally disposed, inwardly protruding portion engaging said recessed region of said holder.

2. The compaction pad of claim 1 wherein said wearcap is formed from hard, abrasion resistant material and said holder is formed from relatively softer, shockresistant material, said wear-cap being shaped such that in the operative position to totally enclose the distal end of said holder.

3. The compaction pad of claim 1 wherein said hollow wear-cap comprises two complimentary cap elements mountable on the distal end portion of said holder, and seams of weld metal deposited on adjacent confronting portions of said two cap elements for retaining the same on said holder.

4. The compaction pad of claim 3 wherein said distal end of said wear-cap includes a substantially enlarged, block-like element, said recessed region being arranged in the side walls of said block-like element, said wearcap including a compaction face and side walls, having said inwardly protruding portions arranged thereon to form a tongue-and-groove joint with said recessed region of said holder.

5. The compaction pad of claim 3 wherein the distal end of said holder is circular in lateral cross-section, said recessed region extending therearound, said wearcap including a generally circular compaction face and side walls having said inwardly protruding portions arranged thereon to form a tongue-and-groove joint with said recessed region of said holder.

6. The compaction padof claim 5 wherein the distal end of said holder includes a generally spherical surface, and a complimentary spherical surface is provided on the inside of said wear-cap opposite from the compaction face thereof for mating engagement with the spherical surface of said holder.

7. A dismountable wear-cap for use with a wear-cap holder comprising a hollow wear-cap member of abrasion-resistant material and having a compaction face and side walls extending around said face, elongated, inwardly extending projections being formed on the inside of said side walls for receipt in a complimentary recess on such wear-cap holder, said wear-cap being formed from two complimentary half-elements configurated along the mating portions thereof for receipt of weld metal.

8. The wear-cap of claim 7 wherein there are included four sidewalls and a generally rectilinear compaction face, said elongated, inwardly extending projections being arranged on confronting side walls.

9. The wear-cap of claim 8 wherein said projections are arranged along the ends of said side walls away from said compaction face.

10. The wear-cap of claim 8 wherein said projections are arranged along medial portions of said side walls.

11. The wear-cap of claim 7 wherein there are included a circular compaction face and curved side walls, a welding backup plate sized to fit in said hollow wear-cap, said compaction face having a hole therein permitting said wear-cap to be welded to said backup plate.

12. The wear-cap of claim ll wherein one surface of said backup plate includes spherical portions for cooperating with the distal end of said wear-cap in a ball and socket bearing relationship.

13. In a compaction pad the combination comprising a replaceable wear-cap and a relatively permanent support therefor, said support including means for mounting the compaction pad fixedly to a compaction wheel, said wear-cap being of hollow, thick shell-like construction and being formed from tough, abrasion resistant material, said wear-cap having an opening for receiving said support through one side of the wear-cap and along the bottom thereof, said support including a head portion formed from shock resistant material and configurated complimentary to the hollow inside portions of said wear-cap and having dimensions which are substantially smaller than the outside dimensions of the wear-cap, the head portion fitting within said hollow wear-cap in an enclosed, snug relationship, and mechanical locking means including complimentary elongate groove and cooperative elongate projection formed on confronting portions of said head portion and the inside walls of said wear-cap, said locking means being arranged within said wear-cap and head portion in a concealed, abrasion protected position.

14. The combination defined in claim 13 wherein said wear-cap is retained in an enclosing relationship with respect to said head portion by means of a seam of weld metal deposited between said head portion and said wear-cap. v

15. A dismountable wear-cap for mounting upon an associated wear-cap holder comprising, a hollow wearcap member formed from a tough, abrasion resistant material in a hollow, thick shell-like construction, said wear-cap having wall structure encompassing three sides of the periphery of the wear-cap and terminating at the bottom to provide an opening along the bottom and one side of the wear-cap permitting receipt of the wear-cap holder in the hollow portion of the wear-cap, and elongated projection means formed integrally with the wall structure and extending inwardly of the inside of said wall structure for mounting in an interlocking relationship in a complementary recess on the associate wear-cap holder.

16. The wear-cap of claim 15 wherein said'wear-cap is formed in an one-piece element and having provided along one side thereof a be vel-like configuration for deposit of weld metal for fixedly retaining said wear-cap on the associated wear-cap holder.

17. The wear-cap of claim 15 wherein said elongated projection means are formed to extend around three sides of said wear-cap.

18. The wear-cap of claim 15 wherein said wear-cap is formed from two complimentary half elements configurated along the mating portions thereof for the receipt of weld metal, and wherein the wall structure is vee-shaped in profile.

19. A compaction wheel comprising an annular wheel-rim member having a plurality of spaced shank members extending radially outwardly from the outer surface of said wheel-rim member, said shank members having radially opening, outwardly tapered sockets arranged therein, wear-cap holers removably mounted in said shank members, said holders including wear-cap supporting head portions and elongated tapered portions extending from said head portions and sized complementary to the tapered sockets in said holders for insertion therein, first locking means on said elongated tapered portions and associated socket wall serving to orient said wear-cap holders with respect to said shanks and to deter relative rotational movements between the holders and shanks, second locking means including openings through said tapered portions and shanks and accessible from the sides of said wheel, fastener means extending through said openings serving to prevent withdrawal of said holders with respect to said shanks, said holders being configurated such that recessed regions are arranged between said head portions and said elongated portions, a plurality of wear-caps on said holders, said wear-caps being of hollow, thick shell-like construction and being formed from tough, abrasion resistant material and having inwardly projecting elongated portions engaging said holders at said recess regions in a relationship wherein said wear-caps substantially enclose said head portions of said holders.

20. The compaction wheel of claim 19 wherein said wear-caps comprise two cap elements united by a seam of weld metal to form a hollow enclosure around the head portions of said holders. 

1. A renewable pad for a compaction wheel comprising a shank having a base adapted to be fixedly secured to a compaction wheel, a longitudinally extending, centrally arranged hole in said shank, a wear-cap holder removably mounted in said shank and having a proximal end inserted into said hole and a distal end projecting therefrom, a hollow, replaceable wear-cap mounted on the distal end of said hoLder, said holder being configurated to include a recessed region about said distal end, said wear-cap including an internally disposed, inwardly protruding portion engaging said recessed region of said holder.
 2. The compaction pad of claim 1 wherein said wear-cap is formed from hard, abrasion resistant material and said holder is formed from relatively softer, shock-resistant material, said wear-cap being shaped such that in the operative position to totally enclose the distal end of said holder.
 3. The compaction pad of claim 1 wherein said hollow wear-cap comprises two complimentary cap elements mountable on the distal end portion of said holder, and seams of weld metal deposited on adjacent confronting portions of said two cap elements for retaining the same on said holder.
 4. The compaction pad of claim 3 wherein said distal end of said wear-cap includes a substantially enlarged, block-like element, said recessed region being arranged in the side walls of said block-like element, said wear-cap including a compaction face and side walls, having said inwardly protruding portions arranged thereon to form a tongue-and-groove joint with said recessed region of said holder.
 5. The compaction pad of claim 3 wherein the distal end of said holder is circular in lateral cross-section, said recessed region extending therearound, said wear-cap including a generally circular compaction face and side walls having said inwardly protruding portions arranged thereon to form a tongue-and-groove joint with said recessed region of said holder.
 6. The compaction pad of claim 5 wherein the distal end of said holder includes a generally spherical surface, and a complimentary spherical surface is provided on the inside of said wear-cap opposite from the compaction face thereof for mating engagement with the spherical surface of said holder.
 7. A dismountable wear-cap for use with a wear-cap holder comprising a hollow wear-cap member of abrasion-resistant material and having a compaction face and side walls extending around said face, elongated, inwardly extending projections being formed on the inside of said side walls for receipt in a complimentary recess on such wear-cap holder, said wear-cap being formed from two complimentary half-elements configurated along the mating portions thereof for receipt of weld metal.
 8. The wear-cap of claim 7 wherein there are included four side walls and a generally rectilinear compaction face, said elongated, inwardly extending projections being arranged on confronting side walls.
 9. The wear-cap of claim 8 wherein said projections are arranged along the ends of said side walls away from said compaction face.
 10. The wear-cap of claim 8 wherein said projections are arranged along medial portions of said side walls.
 11. The wear-cap of claim 7 wherein there are included a circular compaction face and curved side walls, a welding backup plate sized to fit in said hollow wear-cap, said compaction face having a hole therein permitting said wear-cap to be welded to said backup plate.
 12. The wear-cap of claim 11 wherein one surface of said backup plate includes spherical portions for cooperating with the distal end of said wear-cap in a ball and socket bearing relationship.
 13. In a compaction pad the combination comprising a replaceable wear-cap and a relatively permanent support therefor, said support including means for mounting the compaction pad fixedly to a compaction wheel, said wear-cap being of hollow, thick shell-like construction and being formed from tough, abrasion resistant material, said wear-cap having an opening for receiving said support through one side of the wear-cap and along the bottom thereof, said support including a head portion formed from shock resistant material and configurated complimentary to the hollow inside portions of said wear-cap and having dimensions which are substantially smaller than the outside dimensions of the wear-cap, the head portion fitting within said hollow wear-cap in an enclosed, snug relationship, and mechanical locking means including complimentary elongate groove and cooperative elongate projection formed on confronting portions of said head portion and the inside walls of said wear-cap, said locking means being arranged within said wear-cap and head portion in a concealed, abrasion protected position.
 14. The combination defined in claim 13 wherein said wear-cap is retained in an enclosing relationship with respect to said head portion by means of a seam of weld metal deposited between said head portion and said wear-cap.
 15. A dismountable wear-cap for mounting upon an associated wear-cap holder comprising, a hollow wear-cap member formed from a tough, abrasion resistant material in a hollow, thick shell-like construction, said wear-cap having wall structure encompassing three sides of the periphery of the wear-cap and terminating at the bottom to provide an opening along the bottom and one side of the wear-cap permitting receipt of the wear-cap holder in the hollow portion of the wear-cap, and elongated projection means formed integrally with the wall structure and extending inwardly of the inside of said wall structure for mounting in an interlocking relationship in a complementary recess on the associate wear-cap holder.
 16. The wear-cap of claim 15 wherein said wear-cap is formed in an one-piece element and having provided along one side thereof a bevel-like configuration for deposit of weld metal for fixedly retaining said wear-cap on the associated wear-cap holder.
 17. The wear-cap of claim 15 wherein said elongated projection means are formed to extend around three sides of said wear-cap.
 18. The wear-cap of claim 15 wherein said wear-cap is formed from two complimentary half elements configurated along the mating portions thereof for the receipt of weld metal, and wherein the wall structure is vee-shaped in profile.
 19. A compaction wheel comprising an annular wheel-rim member having a plurality of spaced shank members extending radially outwardly from the outer surface of said wheel-rim member, said shank members having radially opening, outwardly tapered sockets arranged therein, wear-cap holers removably mounted in said shank members, said holders including wear-cap supporting head portions and elongated tapered portions extending from said head portions and sized complementary to the tapered sockets in said holders for insertion therein, first locking means on said elongated tapered portions and associated socket wall serving to orient said wear-cap holders with respect to said shanks and to deter relative rotational movements between the holders and shanks, second locking means including openings through said tapered portions and shanks and accessible from the sides of said wheel, fastener means extending through said openings serving to prevent withdrawal of said holders with respect to said shanks, said holders being configurated such that recessed regions are arranged between said head portions and said elongated portions, a plurality of wear-caps on said holders, said wear-caps being of hollow, thick shell-like construction and being formed from tough, abrasion resistant material and having inwardly projecting elongated portions engaging said holders at said recess regions in a relationship wherein said wear-caps substantially enclose said head portions of said holders.
 20. The compaction wheel of claim 19 wherein said wear-caps comprise two cap elements united by a seam of weld metal to form a hollow enclosure around the head portions of said holders. 